looking for PS Audio Power Plant Premier to demo / purchase in Seattle area

PS Audio gives you a 30-day In-home trial of all of their products.

I don't have the line issues you report, but I ordered the Stellar PowerPlant 3 just to "see" if it made any difference. I didn't even want to spend the money for it and I assumed I'd be returning it when I ordered it.

To my surprise it made all my system sound much better and I had to keep it because of the improved SQ I got from it.

I don't see it on the PS Audio website. Is this a current production model?

Try also to audition the Puritan Audio PSM156. This guy found it better in his application than the $10k PS Audio P20.

Puritan PSM156

If you are looking to address DC issues then the PS Audio regenerators won't help you in that department but the Puritan will and I've owned both.  Also the Power Plant you are referencing has been discontinued for years.